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Posted to users@tomcat.apache.org by Wade Chandler <wc...@redesetgrow.com> on 2004/07/01 01:08:18 UTC
Re: Apache -> tomcat connections grow very fast
Stephen Carville wrote:
> Every once in a while, the number of connections between apache and tomcat
> grows very rapidally, going from 12 or so up to over 150 in a matter of about
> 10 minutes. This quickly causes the number of httpd processes to exceed
> MaxClients and apache stops accepting new connections. Restarting tomcat
> relieves the symptom. This is a recent development that first came to my
> attention abtu two weeks ago.
>
> When the problem happens, 'netstat -natp' shows a bunch of connections like:
>
> tcp 0 0 127.0.0.1:39164 127.0.0.1:8009
> ESTABLISHED 21886/httpd
>
> with a corresponding connection for the tomcat end:
>
> tcp 0 0 127.0.0.1:8009 127.0.0.1:39164
> ESTABLISHED 31723/java
>
> Normally there are about 8 to 12 connections between apache and tomcat. I
> cannot figure out why the number suddenly peaks like this. I've scoured the
> http logs and turned on debugging for mod_jk but nothing I've tried so far
> fixes it. I've had the developers do some extra logging to see if any recent
> code changes could be causing it but that too has proved fruitless.
>
> Suggestions are welcome.
>
Do you know what is initiating the connections? 8009 is the connection
between mod_jk and the server. MaxConnections will be on your port 80
or what ever port you are running on. Do you not know the origin of the
other connections? Surely you have connections on the other port 80 or
what ever you are using? Are you using some type of an http protocol
test tool and are you using keep connection?
Wade
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Re: Apache -> tomcat connections grow very fast
Posted by Stephen Carville <st...@totalflood.com>.
On Wed June 30 2004 4:08 pm, Wade Chandler wrote:
> Stephen Carville wrote:
> > Every once in a while, the number of connections between apache and
> > tomcat grows very rapidally, going from 12 or so up to over 150 in a
> > matter of about 10 minutes. This quickly causes the number of httpd
> > processes to exceed MaxClients and apache stops accepting new
> > connections. Restarting tomcat relieves the symptom. This is a recent
> > development that first came to my attention abtu two weeks ago.
> >
> > When the problem happens, 'netstat -natp' shows a bunch of connections
> > like:
> >
> > tcp 0 0 127.0.0.1:39164 127.0.0.1:8009
> > ESTABLISHED 21886/httpd
> >
> > with a corresponding connection for the tomcat end:
> >
> > tcp 0 0 127.0.0.1:8009 127.0.0.1:39164
> > ESTABLISHED 31723/java
> >
> > Normally there are about 8 to 12 connections between apache and tomcat.
> > I cannot figure out why the number suddenly peaks like this. I've
> > scoured the http logs and turned on debugging for mod_jk but nothing I've
> > tried so far fixes it. I've had the developers do some extra logging to
> > see if any recent code changes could be causing it but that too has
> > proved fruitless.
> >
> > Suggestions are welcome.
>
> Do you know what is initiating the connections?
Customers accessing our web site. :-)
> 8009 is the connection
> between mod_jk and the server. MaxConnections will be on your port 80
> or what ever port you are running on. Do you not know the origin of the
> other connections?
By using /server-status page in apache I have a pretty good idea who is
connecting when the problem happens. They are legitimate connections. This
does not appear to be a DOS.
> Surely you have connections on the other port 80 or
> what ever you are using? Are you using some type of an http protocol
> test tool and are you using keep connection?
Yes. The customer connects on port 80 and, if the requested page is a .jsp or
servlet the request is sent along to tomcat via mod_jk on port 8009. Apache
sends the html the JSP generates back to the customers browser. Then the
connection is dropped. It is the next-to-last step where things don't behave
as expected.
I just don't know why nor where to start looking.
> Wade
>
>
>
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--
Stephen Carville
Unix and Network Adminstrator
DPSI
6033 W.Century Blvd.
Los Angeles, CA 90045
310-342-3602
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